Iowan Old Style

Iowan Old Style is a serif typeface designed by John Downer and released by Bitstream in 1991. Iowan Old Style is inspired by serif typefaces from Renaissance Italy, now called the "old-style" or Venetian model of typeface design, with influence from Downer's work as hand-painter of signs. Compared to the historical models it is based on, Iowan has a higher x-height, meaning that the lowercase letters are taller and appear larger and wider, producing a design that is suitable for display and on-screen use. It is used as a default font on the Apple Books application and is included as a system font on iOS and macOS.

From the Wikipedia article “Iowan Old Style”, licensed under CC BY-SA 4.0.

Serif typefaces like this are the traditional choice for book body text: the serifs guide the eye along the line in long passages. Set novels at 10.5–12 pt with 125–140% leading.

Commercial typefaces require a licence that covers embedding in PDFs and ebooks; check the foundry's licence before you publish.